Supporting structures for preparative chromatography columns

ABSTRACT

The plunger used as the upper enclosure in a preparative chromatography column is suspended by one or more rods that are supported by a frame through coupling connections on the frame that can fix the position of the rod(s) relative to the frame, while the position of the rod(s) is controlled by a motorized drive system that is suspended above the column. The drive system is mounted either to the column lid or to a functional plate positioned a short distance above the column lid. These constructions allow the plunger to be raised and lowered so that the column and its parts can be exchanged, all without the need for a hoist or crane.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of co-pending U.S. patent applicationSer. No. 11/955,497, filed Dec. 13, 2007, which claims the benefit ofU.S. Provisional patent application Ser. No. 60/869,819, filed Dec. 13,2006. The contents of both such applications are incorporated herein byreference in their entirety.

BACKGROUND OF THE INVENTION

This invention resides in a frame for supporting and manipulating theparts of a chromatography column of variable packing height and forexchanging columns of different sizes. The chromatography columns withwhich the present invention is primarily contemplated for use arepreparative chromatography columns designed for plug flow of a mobilephase through a packed bed of solid or semi-solid stationary phase. Thewidth of the typical column is large enough that the bed can accommodatea commercially useful throughput rate. In some cases, the column widthexceeds 1 meter. The depth of the column is limited however to maintaina pressure drop low enough to avoid a high pump pressure or a high powerrequirement. Columns of this nature contain a plunger or piston headthat is lowered to contact and compress the solid phase to the desiredheight. With the mobile phase entering the bed from the top, the plungeralso includes a distributor plate to spread the mobile phase across thefull width of the bed, thereby making maximal use of the bed.

The maintenance of these chromatography columns requires that theplunger be periodically removed to perform such functions as replacingits parts, replacing the packed bed, and cleaning the interior of thecolumn. In many cases as well, a column must be exchanged for one of adifferent height or diameter, and a plunger to match. With columns ofthe sizes cited above, these operations typically require a hoist orcrane to lift the plunger and to clear the column from the connectinginstrumentation and supply and discharge lines. These operations arelabor-intensive and capital-intensive. These concerns are particularlyacute when operation of the column requires a clean room or a highclearance above the column, or both.

SUMMARY OF THE INVENTION

The present invention addresses these concerns by providing a frame withcoupling connections that can support the plunger through a suspendingrod or series of rods, combined with a motorized drive system that movesthe rod(s) vertically to cause the plunger to move up and down withinthe column or up and out of the column. In certain embodiments, thecolumn rests on a column skid that can be moved into position within theframe or out of the frame, and the drive system is secured to a movableplatform above the column. In other embodiments, the frame can be movedinto position over the column or out of such position, and the drivesystem is secured to the column lid. In all embodiments, the plunger canbe raised and lowered, and the columns and their component partsexchanged, without the need for a hoist or crane. Certain embodimentsinclude a functional plate that is either specifically constructed for aparticular column or can be used on columns of different diameters, forthe various connections to the top of the column. These and otherobjects, features, and advantages of the invention will be more apparentfrom the accompanying figures and the description that follows.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a preparatory chromatography column andskid, representing one example of this invention.

FIG. 2 is a perspective view of a frame in accordance with thisinvention designed for use with the column and skid of FIG. 1.

FIG. 3 is a front view of a hollow screw which is one of the componentsof the column and skid of FIG. 1.

FIG. 4 is a front view of an upper portion of the column and skid ofFIG. 1 and an upper portion of the frame of FIG. 4 in one position.

FIG. 5 is a front view of an upper portion of the column and skid ofFIG. 1 and an upper portion of the frame of FIG. 4 in a second position.

FIG. 6 is a top view of an upper plate for use in a chromatographycolumn of this invention.

FIG. 7 is a top view of a lower plate for use with the upper plate ofFIG. 6.

FIG. 8 is a front elevation in cross section of a second example of thepresent invention, including a preparative chromatography column and amovable frame.

FIG. 9 depicts the column and frame of FIG. 8 in the same view, exceptwith the column separated from and lifted above its base plate.

FIG. 10 shows as further stage in the manipulation of the column andframe of FIG. 8, with the frame extended vertically.

FIG. 11 is a still further stage in the manipulation of the column andframe of FIG. 8, with the column cover raised above the column.

FIG. 12 shows the column and frame of FIG. 8 with spacers supporting thecolumn cover above the column.

FIG. 13 shows the column and frame of FIG. 8 with the plunger raisedfully out of the column.

DETAILED DESCRIPTION OF THE INVENTION AND PREFERRED EMBODIMENTS

While the features defining this invention are capable of implementationin a variety of constructions, the invention as a whole will be bestunderstood by a detailed examination of specific embodiments. Two suchembodiments are shown in the drawings.

The first of these two embodiments is shown in FIGS. 1 through 7. FIG. 1depicts a column in accordance with the invention and the skid on whichit rests, in condition for use in a chromatographic procedure. While thecolumn tube 10 is typically constructed of stainless steel, it is shownas transparent in FIG. 1 to render the remaining components visible andmore readily understandable. The skid 11 includes a bottom plate 12 anda set of caster wheels 13, while the column mount includes a base (i.e.,lower) ring 14, an upper ring 15, and a series of supporting rods 16(six in this embodiment) joining the two rings and forming a circlearound the peripheries of the rings. A column space is thus definedbetween the lower and upper rings 14, and within the circle formed bythe supporting rods 16. The column tube 10 resides within this space.The plunger 17 (also referred to as a piston head) fits inside thecolumn tube 10 and contains a circumferential gasket 18 that sealsagainst the inner surface of the column tube. The gasket can beinflatable to allow free movement within the column, and into and out ofthe column, when deflated and to seal against the column wall wheninflated. Above the upper ring 15 are a series of spacer rods 19 thatsupport a functional plate 22 (also referred to as a “top plate”) ashort distance above the upper ring 15. The spacer rods 19 aredetachably secured to the functional plate 22 by nuts 20 that engagethreaded extensions (not visible) of the spacer rods, and alsodetachable secured to the upper ring 15 by threaded connections (alsonot visible) extending upward from the upper ring. Secured to thefunctional plate 22 are a gear box 23 and a motor 24, whose functionsare described below. A flow distribution that achieves plug flow, or aflow approximating plug flow, is achieved by distributors inside theplunger 17 and in the center of the base ring 14. The column can be usedeither with the spacer rods 19 in place as shown in FIG. 4 or withoutthe spacer rods, in which case the functional plate 22 is in contactwith the upper ring 22 and the plate and ring can be bolted together byremovable bolts or any removable coupling elements.

The plunger 17 is mounted to the lower end of a central screw 25, whichis a hollow rod threaded on its outer surface. The axis of the centralscrew 25 coincides with the axes of the lower and upper rings 14, 15,the lower and upper rings thus being parallel and coaxial with thecentral screw 25. With its hollow center, this central screw 25 servesas a process line to supply the mobile phase to the column, and theexternal threads of the screw, in conjunction with the gear box 23, forma worm gear for moving the screw 25, and hence the plunger 17, up anddown along the axis. The upper ring 15 has a central opening 26 throughwhich the plunger 17 can be raised when operations require that theplunger be lifted entirely out of the column. The plunger will be liftedout of the column, for example, to clear the column or the plunger forremoval and replacement and for access to the column interior forpurposes of cleaning and other maintenance.

A further component shown in FIG. 1 is a special nut 27. In thisembodiment, knobs protrude from each of two opposing sides of the nut,one knob 28 being visible in the Figure. A still further component shownin the Figure is a screw guide 29. The nut is threaded to complement thethreaded outer surface of the central screw 25 and is movable along thescrew in the axial direction. The functions of the nut 27 and the knobs28 will be apparent from the succeeding figures and description. Ingeneral, however, the knobs 28 serve to couple the nut to the frame.Various alternate structures that are equivalent to these knobs will bereadily apparent to the skilled user. The screw guide 29 stabilizes thecentral screw 25 and helps keep it in alignment.

The frame 31 that supports the upper components of the column skid andassists in their manipulation is shown in FIG. 2. In this embodiment,the frame 31 includes an upright post 32 and two parallel base rails 33,34 supported by caster wheels 35. The base rails 33, 34 are separated bya gap 36 to receive the column skid (FIG. 1), and extending into the gapfrom the post 32 is a brace 37 that will contact the column tube 10(FIG. 1) to stabilize the position of the column and center the columnin the frame. The frame can be constructed in a variety of ways, but itsmost important features are a pair of parallel horizontal beams 41, 42that extend over the area that will be occupied by the column skid andthat will support the entire weight of the column. A controller 43,which is mounted to the frame, includes a pneumatic supply that can beconnected to the plunger gasket 18 (FIG. 1) to inflate the gasket toform a tight seal between the plunger and the column wall. The spacingbetween the horizontal beams 41, 42 allows the passage of the centralscrew 25 and loosely accommodates the nut 27 (FIG. 1), and yet is narrowenough to engage the parallel sides of the nut and thereby prevent thenut from rotating when the nut is between the beams. Each of thehorizontal beams 41, 42 contains a notch 44, 45. Each notch is sized andarranged to receive one of the knobs 28 protruding from the sides of thenut. The frame also includes downwardly depending vertical supports 46,47, 48, 49 that are removable. The function of these supports isdescribed below.

FIG. 3 shows the central screw 25 and the nut 27 separated from theother components. At the base or bottom end of the screw is a mountingflange 51 that can be connected and disconnected from the plunger 17(FIG. 1) by bolts (not shown) for different operations of the unit as awhole. At the top or upper end of the screw is a pipe or tube connection52 to join the screw to a source of supply of the mobile phase whichwill flow through the hollow interior of the screw and into the columntube 10. As noted above, the nut 27 can be manually rotated to vary itsposition along the height of the screw. The nut 27 will occupy differentpositions at different stages of the manipulation of the column and itsvarious connecting parts.

Enlarged side views of two mounting configurations of the various partsof the unit are shown in FIGS. 4 and 5, respectively, including onehorizontal beam 42 of the frame and various components of the columntoward the upper end of the column. In both figures, the plunger 17 israised above the column tube 10. In FIG. 4, the spacers 19 are installedto secure the upper ring 15 to the top plate 22, and the nut 27 ispoised above the horizontal beams of the frame. Operation of the motor24 and gear box 23 will raise and lower the central screw 25 and therebycause the plunger 17 to be lowered into or raised above the column tube10. The column tube can then be emptied and refilled, particularly thosecolumns that are constructed to allow emptying and filling through portsin the bottom. In FIG. 5, the spacers 19 have been removed, and thedownwardly depending vertical supports, of which only two 47, 49 arevisible, have been installed. The top plate 22 is thereby secured to thehorizontal beams 42 of the frame, and the column tube 10 and itssupporting rods 16 can be removed and replaced with a different columnand supporting rods. The plunger 17 can also be disconnected from themounting flange 51 at the lower end of the central screw 25 andreplaced. Also in FIG. 5, the nut 27 has been lowered between thehorizontal beams far enough that the knobs 28 are engaged by the notches45, preventing further downward movement of the central screw 25. Aslotted removable stop ring (not shown) can be inserted above themounting flange 51 to protect the nuts and other fastening components atthe top of the flange 17 from contact with the base top plate 22 andgear box 23. Quick-release pins such as Cotter pins can also be includedto retain the knobs in position inside the notches.

The following is one example of a procedure that can be used to separatethe column tube 10 from the plunger 17. This procedure involves the useof the frame without the vertical supports 46, 47, 48, 49. As notedabove, chromatographic separations can be performed in the column eitherwith the spacer rods 19 in place as shown in FIG. 1 or without thespacer rods (in which case the functional plate 22 is bolted directly tothe upper column ring 15). With or without the spacer rods 19, theseparation procedure is begun by moving the column and skid intoposition against the frame 31 of FIG. 2, with the vertical supports 46,47, 48, 49 having first been removed from the frame. Once the column andskid are in place, the motor 24 is energized, and since the functionalplate 22 to which the motor 24 and gear box 23 are mounted is fixed tothe column (either directly or through the spacer rods 19), the wormgear formed by the central screw 25 and the gear box 23 lifts theplunger 17 upward. When the spacer rods 19 are in place, the motor canpull the plunger out of the column tube 10 and into the gap formedbetween the upper column plate 15 and the functional plate 22 by thespacer rods as shown in FIG. 4. The screw 25 in this raised position isthen coupled to the frame by lowering the nut 27 into the space betweenthe frame beams 41, 42 while placing the knobs 28 in the notches 45, andcoupling the nut to the frame by releasable retaining pins (not shown inthe drawings). With the screw coupled to the frame, the spacer rods 19can then be removed, and the column, including column tube 10, upper andlower rings 14, 15, and column skid 11, can all be rolled out from underthe frame, while the plunger 17 and central screw 25 remain suspendedfrom the frame.

In cases where the column is used with the functional plate 22 bolteddirectly to the upper column ring 15 without the intervening spacer rods19, the functional plate must be disconnected from the upper column ringbefore the plunger can be lifted out of the column. To accomplish this,the bolts securing the plate to the ring are removed either before orafter the column and skid are placed against the frame. This disconnectsnot only the functional plate 22 but also the motor 24, and gear box 23from the column. The screw 25 is then coupled to the frame as describedin the preceding paragraph. With the screw thus immobilized, the motoris then energized, causing the functional plate, motor, and gear box totravel together up the screw 25. This causes the functional plate 22 toseparate from the upper column ring 15, leaving a gap between the plateand the ring, while the plunger 17 remains inside the column.Alternatively, the functional plate 22 can be kept bolted to the uppercolumn ring 15 as the motor is first energized, and as the plunger 17rises within the column tube 10, the motor is turned off as soon as theplunger 17 contacts the underside of the functional plate 22. The boltssecuring the functional plate to the upper ring are then removed and themotor energized once again to lift the functional plate above the ringto form the gap. In either case, once the gap is formed, the spacer rods19 are installed in the gap and securely fastened to both the plate andthe ring. With the spacer rods thus installed, the motor isre-energized, causing the screw 25 and plunger 17 to rise while thefunctional plate, motor and gear box remain stationary. The motorcontinues to run until the plunger 17 clears the upper column ring 15.The spacer rods 19 are then removed as described above, and the column,including column tube 10, upper and lower rings 14, 15, and column skid11, can all be rolled away from the frame, leaving the plunger 17 andcentral screw 25 suspended from the frame.

In all of the above procedures, the plunger 17 can be re-installed inthe column by reversing the procedure.

The following procedure is used for preparing the column for storage.The purpose of this procedure is to close off the top of the column witha cover plate (a solid non-porous disk) and to place the plunger (afterhaving been separated from the screw) on top of the cover plate. Thiscan be done by first raising the plunger 17 out of the column asdescribed in the procedures above, removing the column (by its skid) outfrom under the frame, placing the cover plate over the upper ring 15 ofthe column, and returning the column and skid to the frame. The nut 27on the screw is then engaged by lowering the nut so that the knobs 28are lowered into the notches, and the vertical supports 46, 47, 48, 49(FIG. 5) are then secured to both the functional plate 22 and the frame(with quick-release pins or their equivalent), coupling the functionalplate to the frame. The nut 27 is then raised, first by the motor toclear it from the horizontal beams and the notches, and then by turningthe nut to cause it to travel up the central screw to leave enoughheight between the nut and the plunger so that plunger can be loweredonto the cover plate. With the cover plate directly underneath theplunger, the plunger is then lowered by way of the motor and the centralscrew to rest directly on the cover plate. The mounting flange 51 thatsecures the plunger 17 to the screw is then disconnected from theplunger 17, and the screw is raised (again by the motor) to lift themounting flange from the plunger. The covered column and plunger canthen be rolled out from under the frame for storage.

To lift the plunger from the column cover and remove the column cover sothat the column can be taken from storage and reconnected for use, aprocedure can be followed that is the reverse of the procedure in thepreceding paragraph. With the functional plate 22 already attached tothe frame by way of the vertical supports 46, 47, 48, 49, and thecentral screw 25 also attached to the frame through the functionalplate, the column skid with the covered column and plunger can be movedback into position in the gap 36 between the two parallel base rails 33,34 (FIG. 2) of the frame 31. The central screw 25 is then lowered sothat the mounting flange 51 contacts the plunger 17, and the mountingflange is then secured to the plunger by bolts. The central screw isthen raised to lift the plunger 17 above the cover plate, and the nut 27is lowered to engage the horizontal beams 41, 42. The retaining pins arethen attached to beams to secure the knobs and hence the nut in place.The vertical supports 46, 47, 48, 49 are then removed, and the coverplate is also removed. The spacer rods 19 are then installed atop theupper ring 15 of the column and the functional plate 22 is lowered tocontact the rods. The spacer rods are then secured to both the ring andthe functional plate, thereby affixing the functional plate to thecolumn. The plunger 17 can then be raised higher to allow the column tobe filled from above. By manipulation of the position of the nut 27 andthe central screw 25, the plunger 17 can be lowered into the column toany desired height within the column. The skid containing the column andplunger, with the central screw, functional plate, motor, and all partsnecessary for chromatography can then be moved out from under the framefor use.

For columns in which the functional plate 22 is attached directly to theupper column ring 15, the step of returning the spacer rods 19 to thecolumn can be eliminated.

The structure shown in FIGS. 1 through 5 is useful for a wide range ofcolumn shapes and configurations. Included among these are the EasyPack,GelTec OCS, and InPlace (trademarks of Verdot Industrie, Riom, France)columns. A single functional plate 22 can be designed, for example, thatwill accommodate column tubes of different diameters. The mounts for thecolumn tubes of different diameters will have their own upper and lowerrings (corresponding to upper ring 15 of FIGS. 1, 4, and 5 and the lowerring 14 of FIG. 1) to match the columns. The upper rings can all havethe same diameter, but the upper rings for smaller-diameter columns willhave two sets of screw holes, i.e., an inner set and an outer set. FIG.6 is a top view the upper ring 61 for a column of relatively smalldiameter, while FIG. 7 is a top view of a lower ring 62 for use with theupper ring of FIG. 6.

In the upper ring 61 of FIG. 6, the outer set of screw holes 63 (six innumber in this embodiment) are aligned with the screw holes of thefunctional plate 22, i.e., the holes through which the spacers 19 aremounted, so that the spacers 19 will occupy the same locations for allof the different-sized columns, which are the locations shown in thepreceding figures, and the same functional plate can be used with allupper rings. The inner set of screw holes 64 (six in number in thisembodiment) forms a circle within the circle formed by the outer set 63.The lower ring 62 can have the same diameter as the upper ring 61 or asmaller diameter (a ring with a smaller diameter is shown), but it has asingle set of screw holes 65 (six in this embodiment) that are alignedwith the inner set of screw holes 64 in the upper ring 61. With theinner set of screw holes 64 in the upper ring aligned with the screwholes 65 in the lower ring, the two rings can be joined by a set ofsupporting rods that correspond to the column tube supporting rods 16 ofFIGS. 1, 4, and 5, but that form a smaller circle to place them close toa column tube that likewise has a smaller diameter. Any number ofdifferent diameter column tubes can be accommodated by this type ofconstruction, each having an upper ring of the same outer diameter andan outer set of screw holes at the same locations but with inner sets ofscrew holes at locations specific to each column tube size, togetherwith a lower ring with screw holes aligned with the inner set of theupper ring.

The second embodiment is shown in FIGS. 8 through 13, and containsfeatures similar to those of the first embodiment, except that theplunger is suspended by multiple threaded shafts rather than a singlecentral screw, and the frame of fixed height is replaced by a frame ofvariable height to which the shafts are coupled. This embodiment doesnot require a threaded shaft extending above the frame, and therebyavoids the need for high clearance above the frame. This embodiment alsoavoids the need for removable suspending rods to couple the column tothe frame. This embodiment is particularly suitable for columns that arewider and heavier than those used in the embodiment of FIGS. 1 through7.

FIG. 8 depicts the column tube 81 of this second embodiment. The columntube 81 is closed at its top with a cover plate 82 and at its bottomwith a base plate 83. Passing through the cover plate 82 and into theinterior of the column is a plunger 84 supported by threaded shafts 85,of which three are shown. The mobile phase enters the column through oneor more of the threaded shafts 85 or through an independent set ofpiping, and the plunger 84, whose outer edge is inflatable to sealagainst the inner walls of the column tube as in the embodiment of FIGS.1 through 7, is equipped with a distribution system to spread the flowacross the width of the column and a filter to retain the solids of theslurry in the column. The base plate 83 is likewise equipped with adistribution system and filter for the same purposes as those of theplunger 84. The cover plate 82 and base plate 84 are both secured to thecolumn tube 81 by removable bolts (not shown) or other conventionalmeans that permit dismounting by the operator. The upper ends of thethreaded shafts 85 are mounted to a coupling plate 86, so called in viewof its use in coupling to the frame (as explained below), and each shaftis engaged by a separate gear box 87, with all gear boxes secured to thecoupling plate 86 and driven by a common motor 88. The frame 91 hasvertical legs 92, 93 of variable height supporting an upper beam 94 (ortwo or more beams or a platform), with downwardly extending brackets 95mounted to the underside of the beam 94.

To gain access to the interior of the column from the bottom forpurposes such as cleaning, the frame 91 is first moved into positionover the column by rolling the frame on its caster wheels 96 over thecolumn in such a manner that the brackets 95 slide over and engage theedges of the coupling plate 86, as shown in FIG. 8. Once the column isemptied of its contents through drain lines in the base plate (notshown), the operator then dismounts the column tube 81 from the baseplate 83 and energizes the motor 88. This causes the gear boxes 87 totravel up the threaded shafts 85, raising the column tube 81 and coverplate 82 above the base plate 83, as shown in FIG. 9. The base plate 83can then be removed and replaced with a pallet if desired.

To lift the plunger 84 and to gain access to the interior of the columnfrom the top, the frame 91 is again moved into position as shown in FIG.8, and the motor 88 is energized but without dismounting the column tube81 from the base plate 83. As a result, the motor causes the threadedshafts 85 to rise, which in turn cause the plunger 84 and the couplingplate 86 to rise. The coupling plate 86 pushes the upper beam 94 of theframe upward, extending the legs 92, 93, as shown in FIG. 10. Pegs 101are then placed in exposed holes 102 in the legs, as shown in FIG. 11,to prop up the frame in its raised position, the cover plate 82 isdismounted from the column tube 81 by the operator, and the motor 88 isonce again energized to open the column by raising the cover plate 82above the column tube 81, which is also shown in FIG. 11.

To raise the plunger 84 higher, the frame 91 is extended further. Thisis accomplished by first placing spacers 103 between the cover plate 82and the upper rim 104 of the column tube 81, as shown in FIG. 12. Themotor 88 is then re-energized, causing the threaded shafts 85 to rise,pushing up the coupling plate 86 while the coupling plate pushes up theupper beam 94 of the frame. Pegs 105 are then placed in the newlyexposed holes, as shown in FIG. 13, propping up the frame at its newheight. The spacers 103 can then be removed, and once this is done thecolumn tube 81 and base plate 84 can likewise be removed.

While the foregoing description describes various alternatives to thecomponents shown in the Figures, still further alternatives will beapparent to those who are skilled in the art and are within the scope ofthe invention. In the claims appended hereto, the term “a” or “an” isintended to mean “one or more.” The term “comprise” and variationsthereof such as “comprises” and “comprising,” when preceding therecitation of a step or an element, are intended to mean that theaddition of further steps or elements is optional and not excluded. Allpatents, patent applications, and other published reference materialscited in this specification are hereby incorporated herein by referencein their entirety. Any discrepancy between any reference material citedherein and an explicit teaching of this specification is intended to beresolved in favor of the teaching in this specification. This includesany discrepancy between an art-understood definition of a word or phraseand a definition explicitly provided in this specification of the sameword or phrase.

1. A method for performing preparative chromatography on a mobile phaseby passing said mobile phase through a packed bed, said methodcomprising: (a) placing solid or semi-solid stationary phase in avertical preparative chromatography column comprising (i) a column tubehaving a removable tube cover and a removable tube base, (ii) a plungersuspended by a rod, (iii) a frame configured to detachably engage saidrod, and (iv) motorized drive means mounted to said tube cover formoving said rod vertically to vary the position of said plunger withinsaid column tube; (b) adjusting, by use of said motorized drive means,the height of said plunger to contact said stationary phase and therebyform said stationary phase into a packed bed of a selected height; and(c) introducing said mobile phase to said packed bed through the top ofsaid packed bed to pass through said column tube.
 2. The method of claim1 wherein said plunger is suspended by a plurality of rods, and saidmotorized drive means comprise a single motor for moving all of saidrods simultaneously.
 3. The method of claim 2 wherein said plurality ofrods are supported by a common coupling plate, and said frame isconfigured to detachably engage said rods through said coupling plate.4. The method of claim 2 wherein said frame comprises a horizontal barsupported by vertical supports of extendable height.
 5. The method ofclaim 1 wherein said rod is hollow and step (c) comprises introducingsaid mobile phase to said packed bed through said hollow rod.
 6. Themethod of claim 5 wherein said plunger contains a distribution system todistribute said mobile phase across the width of said column tube.
 7. Amethod for separating a plunger from a preparative chromatography columnfor purposes of cleaning, exchange of the plunger or column, orreplacement of a packed bed within the column, said method comprising:(a) supporting said column on a column support comprising: an upper ringand a lower ring aligned along a common axis and joined to each other byperipheral spacing means to define a column space to receive said columnbetween said rings; a plate detachably joined to said upper ring inparallel relation therewith to define a gap between said plate and saidupper ring; a rod movably joined to said plate along said axis, said rodpassing through said plate and terminating in a plunger that extendsinto said column space; drive means for moving said rod along said axisand thereby moving said plunger within said column space and betweensaid column space and said gap when said plate and said upper ring arejoined; and (b) with said column in said column space and said upper andlower rings, said peripheral spacing means, and said column positionedwithin said frame, lifting, by use of said drive means, said plungerinto said gap; (c) detaching said plate from said upper ring andsuspending said plate from said frame; and (d) removing said upper andlower rings and said peripheral spacing means, with said column therein,from underneath said plunger.
 8. The method of claim 7 wherein said rodis hollow and has a threaded exterior surface, and said drive meanscomprises a motor and gear box affixed to said plate to form a worm gearwith said rod.
 9. The method of claim 7 wherein said peripheral spacingmeans comprises a series of parallel posts joining, and distributedaround the peripheries of, said upper and lower rings.
 10. The method ofclaim 7 wherein said plunger comprises an inflatable peripheral gasket.11. The method of claim 7 wherein said drive means defines a path oftravel of said rod along said axis and said column support furthercomprises means for limiting said path of travel.